Do huge fucking cliffs and invisible walls count as mechanics?
I know equipment durability does and that can fuck right off.
One thing I love is when the game mechanics are well grounded in the world. A recent good example of this was in Tears of the Kingdom; in one cutscene you actually see Zelda use the Purah Pad to fast-travel out of trouble just like you also can. It elevates it from a gaming conceit to something actually part of the world.